Prior to the present invention, crosslinked nylon compositions were prepared by anionic polymerization of a lactam utilizing an epoxy component in the presence of a basic catalyst and a promoter, as shown by Yang, U.S. Pat. No. 4,400,490. Although the nylon compositions of Yang provide useful RIM materials resulting in the production of a variety of valuable molded products, the Yang compositions are primarily a two-component system of lactam and epoxy resin. The two-components mixture must be utilized immediately after mixing to achieve effective results.
The present invention is based on the discovery that anionic polymerization of lactams can be achieved resulting in the production of crosslinked polyamide, or reinforced crosslinked polyamide using certain lactam promoters having silicon attached to the lactam nitrogen by silicon-nitrogen linkages, as defined hereinafter. The base catalyzed crosslinkable blends of lactam and silicon substituted lactam are convertible to high molecular weight polyamide upon heating. In addition, reinforced crosslinked polyamide can be made by incorporating into such silicon-lactam blends, high performance aromatic thermoplastic polymers, such as polyarylene oxides, polyarylene sulfones and polyarylene esters, or inert materials, such as glass fiber or reinforcing silica.